There is a close network of streams, of which one hundred and sixty-five have names. Among the more important are Yellowstone, Lamar, Snake, Gardiner, and Firehole Rivers. There are numerous waterfalls and cascades. The extensive water-flow abundantly supplies the headwaters of the Missouri, Yellowstone, and Snake Rivers. In Two Ocean Pass, among other places, is a lakelet upon the very summit of the Continental Divide whose waters flow to both the Atlantic and the Pacific. The altitude here is 8150 feet, and the lakelet completes a continuous waterway of nearly six thousand miles from coast to coast.
A map that I carried showed Two Ocean Pond on the Continental Divide to the west of the Thumb. There is a Two Ocean Pond on the Divide at that place as well as one to the south of the lake. But my map did not show that the Divide was horseshoe-shaped, and it located the pond on the wrong arm of this horseshoe. Consequently I had a long search before I found the pond, and much confusion with the topography and watersheds after I had discovered it.
One day in 1891 I had the good fortune to come upon General Hiram M. Chittenden. He was directing the cutting of trees at a place that has since become famous as Lake View, from which, perhaps, the best view of Yellowstone Lake is to be had. General Chittenden spent many years in the Park and developed its existing scenic road system. He was the first to propose that the excess of elk and other game in this and other parks be distributed over the country at cost.
What is the greatest feature in this wonderland whose history began at a camp-fire? The Lower Falls thrilled me more than any other waterfall I ever have seen. The Yellowstone Cañon may be called the greatest attraction in this Park. But to me the supreme attraction is the petrified forests.
4. AGES OF FIRE AND ICE
The Yellowstone plateau is a vast lava-deposit. Its material is mostly volcanic, but its landscape—its architecture—is largely glacial. In ages remote, this realm became the scene of volcanic activity. Intermittent outpourings went on through long periods of time. Volcanoes in and near the Park threw forth quantities of ashes, lava, and cinders, which built up a plateau region three or four thousand feet thick. Rhyolite and other forms of lava were last spread over the region. This volcanic activity appears to have ended before the last ice age. No eruption has occurred for centuries. The ice age wrought vast changes in the volcanic landscape. The ice smoothed wide areas, shaped cañons, and rounded mountain-sides, produced and spread soil, and gave the entire region the flowing, attractive lines of glacial landscape.
On the rim of the Yellowstone Cañon, about three miles below the falls, an enormous glaciated granite boulder reposes upon lava—rhyolite. It measures about twenty-four by twenty by eighteen feet. It was transported to this resting-place from mountains more than thirty miles away. Here we have a stone foundation laid by volcanic fire, and upon it a stone, shaped, transported, and placed by glacial ice.
There are about three thousand geysers, hot springs, and mud-and-water springs in the Park; and as many other vents of steam, acid, and gas. That the geysers have been active in this region for thousands of years is shown in the deep deposits of silica and travertine that overspread extensive area. During the ice age many of these deposits were eroded and others were piled with boulders. It is plain that steam and hot water had been at work long before the last ice age came. During the ice period, a wild conflict probably took place between the deep outspread ice and the insistent eruptions of steam and hot water.
The surface of Yellowstone Lake once stood about one hundred and eighty feet higher than it is at present. Its outlet was then through the Snake River to the Pacific Ocean. The Continental Divide then passed over the summit of Mount Washburn. Unwritten as yet is the splendid geological story of this change, which may have been caused by earthquake upheaval or by subsidence. It appears to have occurred about the close of the last glacial epoch. Possibly ice dammed the narrow gorge of Outlet Creek, through which the waters of the lake formerly flowed to the Snake River. Whatever the cause, its outlet waters changed and eroded the now famous and splendidly colored cañon of the Yellowstone.
This is the most celebrated cañon in the Park, and its colors make it one of the most gorgeously startling in the world. At bright noonday, it is adorned with all the hues of the sunset sky. Its precipitous walls are comparatively free from vegetation and are broken with pinnacles and jagged ridges. About fifteen hundred feet below the edge, the rushing waters of the Yellowstone River take on various shades of blue and green between accumulations of gray foam.